This invention relates to improvements in and relating to valves and valve systems for use in controlling the flow of fluids.
In particular the present invention relates to improvements relating to valves and valve systems wherein a valve is used to control the flow of fluid between high pressure and low pressure fluid systems.
In general, the fluid may be a liquid. However, this should not be seen as limiting as the present invention may also be utilized to regulate the flow of other fluids such as gases for example.
Valves which regulate the flow of fluid between high pressure and low pressure fluid systems are known. However, they all suffer from a number of disadvantages.
One type of valve used to regulate the pressure between a high pressure and low pressure fluid system is the pressure reducing or pressure equalizing valve, such as the AJAX(copyright) valve. This type of valve is commonly used to regulate the flow of high pressure (xe2x80x9cHPxe2x80x9d) mains water (generally in the order of 20-100 PSI) as it enters a low pressure (xe2x80x9cLPxe2x80x9d) hot water storage cylinder (generally having a maximum internal pressure threshold of approximately 10 PSI).
In FIG. 1 there is shown a typical prior art standard pressure reducing valve generally indicated by arrow 1. The valve has a valve body 2, an HP inlet 3 connected to a mains water supply and a LP outlet 4 connected to a low pressure hot water storage cylinder. The valve also has a rubber diaphragm 5 which is attached via a bracket 6 to a rubber washer 7. Diaphragm 5 is also attached to a spring 8 which is capable of having its tension adjusted.
The rubber diaphragm 5 is sensitive to pressure changes within the hot water cylinder (xe2x80x9cLP fluid systemxe2x80x9d) and either moves in the direction of arrow A when there is an increase in pressure in the LP fluid system, or moves in the direction of arrow B when there is a decrease in pressure in the LP fluid system.
The sensitivity of the rubber diaphragm 5 to pressure changes within the LP fluid system can be adjusted by altering the tension of spring 8.
When valve 1 is in use, as pressure builds in the LP fluid system this causes washer 7 to also move in direction A and to contact a valve seat 9 to shut off the water supply from inlet 3. Conversely, if the pressure within the LP fluid system is reduced the diaphragm and washer move in the direction of arrow B which allows water to enter the LP fluid system.
However, this type of valve suffers from a number of drawbacks.
One drawback with such valves, is that the seal between washer 7 and valve seat 9 is prone to being compromised due to small particles either damaging or obstructing the sealing face. Thus, this drawback can lead to a constant flow of water into the LP fluid system.
A further disadvantage with such valves is that poor construction of the valve can lead to washer 7 not being in proper alignment with seat 9, thereby allowing HP water effectively to bypass the valve and enter the LP fluid system in an uncontrolled manner.
A further drawback with this type of valve is that if the sensitivity of rubber diaphragm 5 is not adjusted properly HP water can again effectively bypass the valve and enter the LP system.
A further disadvantage with such valves is that if there is an increase in pressure in the mains water supply, this increase may be sufficient to overcome the force being applied to the washer via the diaphragm so that HP water can enter the LP fluid system in an uncontrolled manner.
In addition to the above drawbacks, the use of standard pressure reducing or equalizing valves, such as described in relation to FIG. 1, in commercial or household hot water systems can also create a number of other problems.
The aforementioned type of valve due to its construction requires a hot water cylinder be fitted with a vent pipe. The presence of a vent pipe creates a number of problems which include:
The expense involved in creating a hole through the roof and flashing for the vent pipe;
One pipe circulation in the vent pipe caused by thermo-syphoning resulting in continual power wastage as the hot water that cools in the vent pipe needs to be reheated in the hot water cylinder; and
Burst hot water cylinders caused by frozen vent pipes leading to flooded premises and expensive repairs, as well as to increase the risk of electrocution.
A further disadvantage that occurs with this type of valve is that the diameter of the inlet orifice of the high pressure system must be reduced to allow the pressure of the LP fluid system, as amplified by the diaphragm, to equalize the pressure of the fluid at the HP inlet. As a result, the water pressure from this type of hot water system has a poor flow pressure at most outlets.
Another type of pressure reducing valve which suffers from the same drawbacks as described above is disclosed in NZ 153402/154210. The valve disclosed in this specification uses a flexible sleeve sensitive to pressure changes in a LP fluid system, to cause a valve head to move into or out of contact with a valve seat, located at the end of a high pressure fluid inlet.
It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.
Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.
According to one aspect of the present invention there is provided a valve assembly which includes:
At least one valve port;
At least one fluid inlet; and
An outlet for connection to a fluid system;
characterized in that the valve assembly includes a pressure sensitive member which is connected to the outlet, so that the size of the pressure sensitive member is capable of increasing or decreasing in response to pressure changes within the fluid system, wherein the valve is configured so that said increases or decreases to the size of the pressure sensitive member cause the inlet and valve port to move either into or out of alignment with one another.
According to another aspect of the present invention there is provided a valve assembly substantially as described above wherein the valve assembly includes a relief outlet.
According to another aspect of the present invention there is provided a valve assembly substantially as described above wherein the valve assembly includes a relief outlet, characterized in that the valve assembly is configured so that the pressure sensitive member will increase in size to an extent that enables the member to move the relief outlet and valve port into alignment with one another, if a predetermined pressure threshold limit is reached.
According to a further aspect of the present invention there is provided a valve assembly wherein the valve assembly (xe2x80x9cMod Assemblyxe2x80x9d) includes:
a) At least one valve port;
b) A first opening;
c) Second opening or openings;
d) Third opening or openings; and
e) A pressure sensitive member;
characterized in that the valve assembly is configured so that the position of the pressure sensitive member is capable of being altered solely in response to pressure changes within a fluid system to which the first opening is connected, wherein said changes in the position of the pressure sensitive member cause the valve port to move either into or out of alignment with the second or third opening, so that the valve port is moveable to each of the following positions:
a) At least partially aligned with the second opening or openings but not the third opening or openings; or
b) At least partially aligned with the third opening or openings but not the second opening or openings; or
c) Non-aligned with either the second or third openings.
According to another aspect of the present invention there is provided a method of operating a valve assembly connected to a high pressure inlet of a relatively low pressure fluid system so as to regulate inlet flow into the system, the method characterized by the step of:
a) Utilizing a pressure sensitive member to move at least one valve port and fluid inlet either, into, or out of, alignment with one another, when the pressure within the fluid system increases or decreases.
According to another aspect of the present invention there is provided a method, substantially as described above, characterized by the additional step of:
b) Utilizing the pressure sensitive member to move the valve port or ports and at least one relief outlet into alignment with one another, if a predetermined pressure threshold limit is reached.
According to a further aspect of the present invention there is provided a method of operating a valve assembly connected via a first opening to a fluid system, to regulate over-pressure and under-pressure situations within the system, via a pressure sensitive member, the method characterized by the steps of:
a) Moving the valve port or ports and second opening or openings into at least partial alignment with one another; or
b) Moving the valve port or ports and third opening or openings into at least partial alignment; or
c) Moving valve port or ports so as to be non-aligned with either the second or third openings.
The present invention relates to improvements relating to valves and valve systems wherein a valve is generally used either to control the flow of fluid between relatively high and low pressure fluid systems or regulate the pressure within a fluid system or to do both.
In general, the fluid may be a liquid. However, this should not be seen as limiting inasmuch as the present invention may also be utilized to regulate the flow of other fluids such as gases for example.
The valve port or ports may be either the same or a different orifice or orifices within the valve assembly capable of allowing fluid either to enter or to exit the valve assembly, or to do both.
The inlet of the valve assembly in some embodiments may itself be connected to the terminal end of a conduit transporting fluid from a high pressure (xe2x80x9cHPxe2x80x9d) fluid supply.
However, in preferred embodiments the inlet of the valve assembly may be an orifice within the valve assembly which is not situated directly at the point where the valve connects to the conduit transporting the fluid from an HP fluid supply.
The outlet in preferred embodiments maybe an opening in the valve assembly which allows fluid to exit the valve assembly and enter a low pressure (xe2x80x9cLPxe2x80x9d) fluid system. However, as the pressure in the LP fluid system rises fluid is able to enter the valve assembly from the LP fluid system via this opening.
In general, the outlet may be connected to a conduit leading to the LP fluid system. However, this should not necessarily be seen as limiting the scope of the present invention.
It is envisaged that the pressure sensitive member may come in a variety of different forms and be made of a variety of different materials.
In general, the shape, configuration or materials or any combination thereof from which the pressure sensitive member is made should enable the size of the pressure sensitive member either to increase or decrease in response to pressure changes.
The pressure sensitive member may be composed of a substantially resilient material.
In preferred embodiments the pressure sensitive member may be composed of rubber or other compounds having similar characteristics.
In some embodiments of the present invention the pressure sensitive member may in its configuration resemble a balloon or flexible corrugated bellows.
In some other embodiments the pressure sensitive member may be in the form of a substantially elongate hollow cylinder or other similar shape.
In preferred embodiments the pressure sensitive member may be in the form of a diaphragm.
However, it should be appreciated by those skilled in the art that the pressure sensitive member may also have other configurations or be composed of other materials, or both, without departing from the scope of the present invention.
In some embodiments, the size of the pressure sensitive member which alters, upon an increase or decrease in pressure, is the length of the pressure sensitive member.
In such embodiments to help ensure that a change in pressure results in the length of the pressure sensitive member being altered, the pressure sensitive member may be housed within a rigid casing, to minimize any lateral expansion of the member.
In preferred embodiments the surface area of the pressure sensitive member may increase or decrease in response to pressure changes in the LP system.
It is envisaged that the pressure sensitive member may be connected to the outlet in a variety of different ways, without limiting the scope of the present invention.
In preferred embodiments the PSM may be located in a valve chamber to which the outlet is connected.
In some embodiments where it is the length of the pressure sensitive member that is altered, the pressure sensitive member may be attached to a lower valve body, said lower valve body including the outlet.
The valve port may have a variety of different configurations without departing from the scope of the present invention.
In general, the valve port may be located in a valve head.
In preferred embodiments the valve head may have at least its sealing face composed of a ceramic or similar material, and the outer face of the fluid inlet which abuts the sealing face of the valve head may also be composed of ceramic or similar material.
In preferred embodiments the valve head may be in the form of a disc composed of a ceramic or similar material. In such embodiments the fluid inlet or inlets may be also located in a ceramic disc.
In most embodiments where it is the length of the pressure sensitive member which is altered, the perimeter of the sealing face of the valve head, may be enclosed by a portion of the valve body composed of ceramic material.
This portion of the valve body substantially corresponds to the shape and dimensions of the perimeter of the valve head. Thereby the valve head is enabled to move relative to the surrounding ceramic material in a fluid-tight manner. In such embodiments the valve head may generally be in the form of a stem.
It should be appreciated by those skilled in the art, that the valve head and outer face of the inlet may be composed of other materials provided they allow the valve head and outer face of the fluid inlet to move with respect to one another in a fluid-tight manner.
In preferred embodiments, the valve port or ports move substantially laterally with respect to the inlet and the direction of fluid flow through the inlet of the valve assembly.
The inventor has found the advantage provided by lateral movement of the port is that it enables a positive on or off disposition to be achieved when the port is moved into or out of alignment with the fluid inlet.
In all preferred embodiments, the size of the pressure sensitive member alters as a result of pressure changes that occur within the LP fluid system to which the outlet of the valve assembly is connected.
In general, the size of the pressure sensitive member will decrease when the pressure in the LP fluid system drops, and conversely will increase when the pressure within the LP system rises.
In preferred embodiments the construction of the valve assembly is such that the valve port and inlet may be moved into alignment with one another, by the pressure sensitive member, when the pressure in the LP fluid system falls below a predetermined pressure. Conversely, the valve port and inlet will be moved out of alignment, by the pressure sensitive member, when the pressure in the LP fluid system rises above a predetermined pressure.
It is envisaged that the sensitivity of the pressure sensitive member will be governed by the maximum pressure of the LP fluid system the valve assembly will be regulating.
Once the valve port and inlet are no longer in alignment should the pressure in the LP fluid system continue to rise above a predetermined maximum pressure threshold, excess fluid may be released from the valve assembly to relieve the pressure build-up in the LP fluid system.
It is envisaged that the relief of pressure from within the LP fluid system may occur in a variety of different ways.
In some embodiments, the valve assembly may include a spring loaded relief valve which opens when the pressure within the valve assembly reaches a maximum predetermined pressure threshold, thereby to relieve pressure in the LP fluid system.
In preferred embodiments, the continual build up of pressure to the maximum pressure threshold in the LP fluid system, causes the size of the pressure sensitive member to increase further, so that the valve port or ports can be brought into alignment with a relief outlet. By this means fluid may exit the valve assembly to help relieve pressure within the LP fluid system.
It is envisaged there may be a variety of different ways in which changes to the size of the pressure sensitive member may cause the valve port or ports and inlet or inlets to move into and out of alignment with one another.
In some embodiments, the increasing or decreasing length of the pressure sensitive member may cause it or another part of the valve assembly to contact at least one switch which activates at least one solenoid which then moves the valve port or ports either into or out of alignment with the fluid inlet or inlets.
In other embodiments, the pressure sensitive member may be attached to an upper valve body which includes the fluid inlet or inlets. The pressure sensitive member also being connected to a lower valve body which includes the fluid outlet. The valve port being arranged so that it does not move relative to the lower body. Consequently, increases and decreases in the length of the pressure sensitive member cause the fluid inlet to move either into or out of alignment with the valve port.
In such embodiments, the pressure sensitive member may be attached to the upper valve body in variety of different ways without limiting the scope of the present invention.
In preferred embodiments, increasing or decreasing the surface area of the pressure sensitive member may act to cause rotation of a valve head in the form of a disc including at least one valve port such that the port moves either into or out of alignment with the fluid inlet.
It should be appreciated that as an alternative to the above configurations, the pressure sensitive member may be configured so that it is able to contact the valve head to bring the valve port into or out of alignment with the fluid inlet.
Movement of the pressure sensitive member may also in some preferred embodiments move valve port or ports into and out of alignment with the pressure relief outlet.
In general it is envisaged that the present invention will be utilized in either domestic or commercial hot water systems to regulate the flow of HP mains water into an LP hot water cylinder. However, this should not be seen as limiting.
In relation to the Mod Assembly:
a) The first opening is functionally equivalent to the outlet of the valve assembly;
b) The second opening is generally functionally equivalent to the fluid inlet of the valve assembly described above; and
c) The third opening is generally functionally equivalent to the relief port of the valve assembly described above.
However, in some situations of the present invention in particular the Mod Assembly may be utilized solely as a pressure relief valve, and will not regulate the flow of HP mains water into an LP fluid system.
For ease of reference only, the use of the present invention as a pressure relief valve will now be described in relation to the Mod Assembly.
When the Mod Assembly of the present invention is being used solely as a pressure relief valve it will not be connected to the HP inlet of an LP fluid system. By way of contrast, the first opening of the valve assembly will instead be connected to the LP fluid system.
The second opening or openings will be connected to an exhaust conduit and the third opening or openings will be connected to the outside environment. The purpose of the second opening or openings to allow for fluid to exit the LP fluid system when the valve port is aligned with the second opening or openings so as to relieve an over-pressure situation in the LP fluid system. Conversely, the purpose of the third valve opening or openings is to allow for the entry of air into the LP fluid system when the port and third opening or openings are aligned, so as to relieve a negative pressure situation in the LP fluid system.
To function as a relief valve the Mod valve assembly needs to be reconfigured so that:
a) The valve port is not aligned with the second or third opening or openings, when the fluid system is in a xe2x80x9cneutralxe2x80x9d situation (i.e. not in an over- or under-pressure situation);
b) The valve port is aligned with the second opening or openings but not the third opening or openings when the fluid system is in an over-pressure situation; and
c) The valve port is aligned with the third opening or openings but not the second opening or openings when the fluid system is in an under-pressure situation.
It should be appreciated by those skilled in the art, that when the present invention is attached to an LP system so as to act solely as a relief valve; the regulation of the HP fluid flow into the LP system may be undertaken by any suitably configured valve assembly.
Thus, preferred embodiments of the present invention may have a number of advantages over the prior art.
One advantage of the present invention is that the valve provides a positive on or off disposition for regulating fluid flow into an LP fluid system. Furthermore, due to its construction the valve assembly of the present invention is not prone to being compromised due to small particles in the fluid.
A further advantage of the present invention is that any increase in the pressure of the inlet fluid flow will not cause the valve effectively to be bypassed.
A further advantage of certain embodiments of the present invention is that they contain, or can act as, a pressure relief valve capable of relieving pressure in the LP fluid system due to thermal expansion, or to cover the situation where the valve should fail for any reason.
Further advantages of the present invention when used in either a domestic or commercial hot water system may include one or both of the following:
(i) There is no requirement for the hot water cylinder to be fitted with a vent pipe, so that none of the related problems associated with vent pipes occur; and
(ii) A full flow hot water can be supplied inasmuch as there is no requirement to reduce the diameter of the inlet orifice.
Another advantage of the present invention is that the valve assembly may also be connected to an LP fluid system so as to act solely as a pressure relief valve.